1. Technical Field
The present invention relates to an image processing apparatus, an image processing method and a computer readable medium. More particularly, the present invention relates to an image processing apparatus and an image processing method for processing images, and a computer readable medium for use in the image processing apparatus.
2. Description of the Related Art
A known moving image coding apparatus compares a coded screen image and a to-be-coded screen image in order to identify a changed region within the screen, divides the to-be-coded screen image into a plurality of image blocks, and codes image blocks including the changed region, for example, as disclosed in Japanese Patent No. 2828977. When coding the image blocks including the changed region, this moving image coding apparatus assigns a larger number of information bits to image blocks containing a further limited region of the changed region than to image blocks containing the remaining region of the changed region. Also, a known digital image generating method generates additional information relating to the importance of a subject of a digital image and a background region corresponding to the subject, and saves a compressed digital image resulting from compressing the digital image in association with the additional information, for example, as disclosed in Japanese Patent Application Publication No. 2003-250132. There is a known video recorder/player that changes the level of compressing input data dynamically according to the importance of the data, and stores important data with a small compression level (see, e.g., Japanese Patent Application Publication No. 2003-189242). Further, there is a known moving image compressor that keeps the image of a monitored object displayed on the screen of a monitor clear even when the image data supplied from the monitoring camera includes a large motion, to allow the viewer to sufficiently observe the situation of the monitored area (see, e.g., Japanese Patent Application Publication No. 10-70716).
The techniques disclosed in the above-mentioned patent documents, however, can not compress each of a plurality of regions according to the character of the region. The invention of Japanese Patent Application Publication No. 2003-189242 determines a motion vector based on a displacement vector of a moving region. The invention of Japanese Patent Application Publication No. 10-70716 can increase the quantization coarseness of a moving region. However, the techniques of Japanese Patent Application Publication No. 2003-189242 and Japanese Patent Application Publication No. 10-70716 cannot compress images with a suitable compression rate, because the techniques cannot compress and code any object in a moving region in a way adapted to the object.